Electric pile sealing structure and battery electric pile

Abstract

The invention provides a galvanic pile sealing structure and a battery galvanic pile, the galvanic pile sealing structure comprises a first metal pole plate, a second metal pole plate and a sealing member, the sealing member is arranged between the first metal pole plate and the second metal pole plate, the sealing member comprises a first bonding layer, an elastic layer and a second bonding layer which are laminated, the first metal pole plate is provided with a first elastic convex groove protruding towards the sealing element, the second metal pole plate is provided with a second elastic convex groove protruding towards the sealing element, the first bonding layer is bonded with the top surface of the first elastic convex groove, and the second bonding layer is bonded with the top surface of the second elastic convex groove. The sealing structure disclosed by the invention can ensure that each metal polar plate of the stacked single batteries is uniformly stressed, so that gaps between the metal polar plates of the adjacent single batteries are avoided, and meanwhile, the pressure required for assembling the galvanic pile is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of electrochemical batteries, and in particular to a battery stack sealing structure and a battery stack. Background Art

[0002] Metal plates are important components in electrochemical cells such as fuel cells and flow batteries. The battery stack is composed of multiple cells, each of which is composed of a membrane electrode assembly and metal cathode plates and metal anode plates on both sides. When assembling the battery stack, multiple cells need to be stacked up, and the cathode plates and anode plates of adjacent cells need to be sealed to ensure that the fluid flows in the designed flow field without internal leakage or external leakage.

[0003] In the prior art, the metal plates of adjacent cells are sealed by a pressure-type sealing structure. Figure 1 As shown, a groove 12 is provided on the first metal plate 1 of a single cell, and a sealing strip 5 is installed in the groove. When the battery is assembled, an external force is applied to squeeze the sealing strip 5 on the second metal plate 2 of the adjacent single cell, and the sealing strip 5 is deformed. After packaging, there is a large contact force between the sealing strip 5 and the metal plates on both sides, thereby achieving extrusion sealing. However, in order to ensure the sealing effect of this structure, a large pressure needs to be applied to the metal plates, which brings the following problems: (1) Impact on battery performance: When assembling a battery stack, hundreds of cells are stacked together. It is impossible to ensure that each metal plate of each cell is subjected to the same force. Metal plates at different assembly positions will inevitably produce pressure differences. At the same time, in order to ensure the sealing effect, it is necessary to apply a pressure that meets the standard to the metal plate with the least pressure. At this time, other metal plates will be subjected to pressure exceeding the standard. The thickness of the metal plate itself is very small. The metal plate that is subjected to excessive pressure will deform, causing the flow channel on the metal plate to deform and compress, reducing the fluid intake of the single cell and reducing performance.

[0004] (2) Impact on battery life: The metal plate and sealing strip of the pressure-type sealing structure form a structure similar to a simply supported beam, which will result in local stress concentration and easily cause deformation and damage to the metal plate. Due to the existence of assembly tolerances, there may be gaps between some metal plates and the sealing strip, allowing water to enter the flow field and corrode the metal plate, resulting in a shortened battery life.

[0005] (3) High production cost: The pressure-type sealing structure must ensure that the sealing strip and the metal plate have a large extrusion force. Accordingly, a large assembly force must be applied during assembly, so special pressure packaging equipment is required, which increases the equipment cost. In addition, the sealing strip must withstand a large pressure, which requires strict material selection and high material cost. Summary of the invention

[0006] In view of the deficiencies of the prior art, the purpose of the present invention is to provide a new battery stack sealing structure to ensure that the stacked metal plates are evenly stressed, avoid gaps between the metal plates of adjacent cells, and reduce the pressure required for battery stack assembly.

[0007] To achieve the above-mentioned purpose, the present invention provides a battery stack sealing structure, including a first metal pole plate, a second metal pole plate and a seal, the first metal pole plate is the cathode / anode plate of a single battery, the second metal pole plate is the anode / cathode plate of another adjacent single battery, the seal is arranged between the first metal pole plate and the second metal pole plate, the seal includes a first bonding layer, an elastic layer and a second bonding layer which are stacked, the first metal pole plate has a first elastic convex groove protruding toward the seal, the second metal pole plate has a second elastic convex groove protruding toward the seal, the first bonding layer is bonded to the top surface of the first elastic convex groove, and the second bonding layer is bonded to the top surface of the second elastic convex groove.

[0008] The present invention absorbs pressure together by means of elastic grooves arranged on the metal plates on both sides and the elastic layer of the seal. The elastic grooves and the elastic layer have a pressure regulating function, so that the stacked metal plates are subjected to uniform force, deformation of the metal plates is avoided, and the performance of each single battery is guaranteed to be consistent. The seal is bonded to the elastic grooves of the metal plates on both sides. Even if there is an assembly tolerance, the bonding force between the bonding layer and the metal plates can avoid the appearance of gaps between the seal and the metal plates, thereby ensuring the sealing effect. This sealing structure achieves sealing by bonding the bonding layer and the elastic groove surface, and a good sealing effect can be achieved without applying a lot of pressure. Therefore, the assembly force required for assembly is small, which is beneficial to reducing equipment and material costs. It is also easy to disassemble and assemble, and the single battery can be repeatedly assembled.

[0009] Preferably, the materials of the first adhesive layer and the second adhesive layer are pressure-sensitive adhesive, and the material of the elastic layer is rubber. The seal adopts a sandwich structure, and the adhesive layer is bonded to the elastic convex groove after being subjected to a small pressure, eliminating the gap between adjacent metal plates and achieving a good sealing effect; the assembly pressure is mainly absorbed by the elastic convex groove, and when overpressure is generated, the elastic layer deforms to absorb excess pressure to avoid damage to the metal plate.

[0010] Preferably, the thickness of the elastic layer is in the range of 300-600 μm. The elastic layer has a certain thickness to offset the assembly tolerance and ensure the contact between the adhesive layer and the elastic groove; the thickness of the elastic layer should not be too large to avoid local stress concentration.

[0011] Preferably, the projection of the seal on the first metal plate covers the first elastic convex groove, and the projection of the seal on the second metal plate covers the second elastic convex groove. The seal covers the area where gaps may occur, while increasing the contact area with the elastic convex grooves on both sides, dispersing pressure and avoiding stress concentration.

[0012] Preferably, the cross-section of the first elastic convex groove and the second elastic convex groove is an isosceles trapezoid with an upper bottom angle ranging from 120° to 160°. The isosceles trapezoid structure ensures that the elastic convex groove has good structural strength and elasticity and can automatically adjust the pressure.

[0013] Preferably, the width of the groove top surface of the first elastic convex groove is in the range of 1-2 mm, the width of the inclined surface of the first elastic convex groove is in the range of 0.4-0.6 mm, the width of the groove top surface of the second elastic convex groove is in the range of 1-2 mm, and the width of the inclined surface of the second elastic convex groove is in the range of 0.4-0.6 mm. By limiting the width and inclination angle of the elastic convex groove, the protrusion height of the elastic convex groove can be controlled, thereby ensuring that the flow channel size is within the design range; and the width of the groove top surface and the width of the inclined surface are controlled in an appropriate ratio to ensure that the pressure can be transmitted to the inclined surface when the groove top surface is subjected to force, and the pressure is adjusted through elastic deformation.

[0014] Preferably, the seal has an overlap area that contacts both the groove top surface of the first elastic convex groove and the groove top surface of the second elastic convex groove. The overlap area is where the elastic convex grooves on both sides overlap and cover the seal, and the two elastic convex grooves and the seal work together to absorb pressure.

[0015] Preferably, the width of the overlap area is greater than or equal to 0.5 mm. When designing the stack sealing structure, the width of the overlap area where the elastic convex grooves on both sides overlap and cover the seal is as large as possible. Due to the assembly tolerance, the relative positions of the elastic convex grooves on both sides will be offset during assembly, but this sealing structure can absorb larger assembly tolerances. As long as the width of the overlap area is not too small, the sealing effect can be guaranteed.

[0016] Preferably, the width of the top surface of the first elastic convex groove is greater than that of the second elastic convex groove, and the wall thickness of the first elastic convex groove is greater than that of the second elastic convex groove. In this way, the deformation of the second elastic convex groove can be controlled to be greater than that of the first elastic convex groove, so that the sealing structure between each single battery is consistent after being stressed, eliminating the influence of assembly tolerance.

[0017] The present invention also provides a battery stack, comprising the above-mentioned battery stack sealing structure.

[0018] In summary, compared with the prior art, the present invention has the following beneficial effects: (1) The stack sealing structure is composed of seals and elastic grooves on both sides to jointly adjust the pressure, so that the stacked metal plates are evenly stressed and no metal plate is overstressed, thereby ensuring that the flow channel size between the metal plates is stable and the performance of each single battery is uniform.

[0019] (2) The seal fits the elastic groove and has a large contact area, which will prevent local stress concentration and avoid damage to the metal plate.

[0020] (3) The seal is bonded to the metal plates on both sides to avoid gaps between the seal and the metal plates, ensuring the sealing effect and helping to extend the battery life.

[0021] (4) The seal is achieved by bonding the sealant to the metal plate, which greatly reduces the pressure required for assembly, reduces the cost of assembly equipment and sealing materials, and facilitates assembly and disassembly.

[0022] (5) Since the assembly pressure is small and the deformation of the seal is small, the single cells in the battery stack can be disassembled and reassembled while still ensuring the sealing performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic diagram of the cross-sectional structure of the battery stack sealing structure in the prior art.

[0024] Figure 2 Schematic diagram of the cross-sectional structure of the stack sealing structure in an embodiment of the present invention.

[0025] Figure 3 Schematic diagram of the cross-sectional structure of the sealing member in an embodiment of the present invention.

[0026] Figure 4 It is a diagram showing the cross-sectional dimensions of the stack sealing structure in an embodiment of the present invention.

[0027] Figure 5 It is a schematic diagram of the cross-sectional structure of the battery stack seal in another embodiment of the present invention.

[0028] Description of reference numerals:

[0029] 1-first metal plate, 11-first elastic convex groove, 12-groove, 2-second metal plate, 21-second elastic convex groove, 3-sealing member, 31-first adhesive layer, 32-elastic layer, 33-second adhesive layer, 34-overlapping area, 4-membrane electrode, 5-sealing strip. DETAILED DESCRIPTION

[0030] In order to make the above-mentioned purposes, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. It should be noted that the following embodiments are only used to illustrate the implementation method and typical parameters of the present invention, and are not used to limit the parameter range described in the present invention. Reasonable changes derived therefrom are still within the scope of protection of the claims of the present invention.

[0031] The battery stack is the core component of the electrochemical battery, including multiple stacked single cells and current collectors. Each single cell is composed of a membrane electrode 4 and a first metal plate 1 (cathode / anode plate) and a second metal plate 2 (anode / cathode plate) arranged on both sides of the membrane electrode 4. After multiple single cells are stacked, the first metal plate 1 of a single cell is sealed and connected to the second metal plate 2 of an adjacent single cell. The sealing structure is generally set at the edge of the metal plate body and the edge of the three-cavity opening, and a coolant flow field is formed between the adjacent first metal plate 1 and the second metal plate 2.

[0032] Combination Figures 2 to 5 As shown, this embodiment provides a sealing structure for sealing adjacent single cells, including a sealing member 3 disposed between a first metal plate 1 and a second metal plate 2, a first elastic convex groove 11 protruding toward the sealing member 3 on the first metal plate 1, and a second elastic convex groove 21 protruding toward the sealing member 3 on the second metal plate 2. The first elastic convex groove 11 / the second elastic convex groove 21 is integrally formed with the first metal plate 1 / the second metal plate 2, generally formed by a stamping process, has a certain elasticity, and will undergo elastic deformation after being subjected to force, thereby absorbing the pressure on the metal plates and automatically adjusting so that the forces on each metal plate are uniform.

[0033] Combination Figure 3 As shown, the seal 3 includes a first adhesive layer 31, an elastic layer 32 and a second adhesive layer 33 which are stacked. The first adhesive layer 31 is bonded to the top surface of the first elastic convex groove 11, and the second adhesive layer 33 is bonded to the top surface of the second elastic convex groove 21. This sealing structure is sealed by bonding the adhesive layer and the elastic convex groove surface. It does not require a lot of pressure to achieve a good sealing effect, and the bonding force can eliminate the influence of assembly tolerance on sealing, ensuring that no gap will appear between the seal 3 and the metal plate.

[0034] The material of the elastic layer 32 in the seal 3 is an elastic material, preferably rubber, which can absorb overpressure by deformation to avoid damage to the metal plate, and will not be over-compressed. After the pressure is removed, the deformation of the elastic layer 32 can be partially restored, and the sealing performance can still be guaranteed after the single battery in the battery stack is disassembled and reassembled. The material of the first adhesive layer 31 and the second adhesive layer 33 is a viscous material, preferably a pressure-sensitive adhesive, which is bonded to the top surface of the elastic convex groove after being subjected to assembly pressure.

[0035] Combination Figure 2and Figure 4 As shown, in this embodiment, the seal 3 has a larger width, covering the area where gaps may occur, and its projection on the first metal electrode plate 1 covers the first elastic convex groove 11, and its projection on the second metal electrode plate 2 covers the second elastic convex groove 21, ensuring that the top surfaces of the elastic convex grooves on both sides are completely in contact with the seal 3, and the contact surface is large enough to ensure the sealing effect and avoid stress concentration.

[0036] In this embodiment, the cross-section of the first elastic convex groove 11 and the second elastic convex groove 21 is an isosceles trapezoid, and the upper bottom angle is 145°. This structure enables the elastic convex groove to have good structural strength and elasticity, thereby playing a role in supporting and absorbing assembly pressure. In some optional embodiments, the cross-section of the first elastic convex groove 11 and the second elastic convex groove 21 is an isosceles trapezoid, and the upper bottom angle ranges from 120° to 160°.

[0037] In other embodiments, the cross-section of the first elastic groove 11 and the second elastic groove 21 is a double-layer isosceles trapezoid. This structure has better elasticity, but when the overall width of the elastic groove remains unchanged, the width of the top surface of the groove will decrease, and the sealing surface area in contact with the seal 3 will be reduced.

[0038] Combination Figure 4 As shown, in this embodiment, the first elastic convex groove 11 and the second elastic convex groove 21 are symmetrical structures with the same size. The width W1 between the first elastic convex groove 11 and the groove top surface and the width W2 between the second elastic convex groove 21 and the groove top surface are both 1.9 mm, the width L1 of the inclined surface of the first elastic convex groove 11 and the width L2 of the inclined surface of the second elastic convex groove 21 are both 0.45 mm, and the width of the groove top surface and the width of the inclined surface are controlled in an appropriate proportion to ensure that when the groove top surface is subjected to force, the pressure can be transmitted to the inclined surface, and the pressure is absorbed by elastic deformation to automatically adjust the force on each metal plate.

[0039] In other embodiments, the sizes of the first elastic groove 11 and the second elastic groove 21 may be the same or different, and the width W1 of the groove top surface of the first elastic groove 11 is limited to between 1 and 2 mm, and the width L1 of the inclined surface is limited to between 0.4 and 0.6 mm; the width W2 of the groove top surface of the second elastic groove 21 is limited to between 1 and 2 mm, and the width L2 of the inclined surface is limited to between 0.4 and 0.6 mm, thereby controlling the pressure absorption effect and the protruding height of the elastic groove, and ensuring that the flow channel dimensions of the first metal electrode plate 1 and the second metal electrode plate 2 are within the design range.

[0040] In this embodiment, the thickness D of the elastic layer 32 is 600 μm. The elastic layer 32 has a certain thickness, which can offset the assembly tolerance and ensure that the adhesive layer is in contact with the elastic protruding groove. In other embodiments, in order to avoid local stress concentration, the thickness D of the elastic layer 32 is limited to 300-600 μm, and the thickness of the first adhesive layer 31 and the second adhesive layer 33 is generally less than or equal to 5 μm, which has little effect on the overall thickness of the seal 3.

[0041] Combination Figure 5 As shown, the seal 3 has an overlapping area 34 that contacts the top surface of the first elastic groove 11 and the top surface of the second elastic groove 21 at the same time. In the overlapping area 34, the first elastic groove 11, the second elastic groove 21 and the seal 3 can play a synergistic role to automatically adjust the pressure on the metal plate.

[0042] In an ideal situation, the first elastic protrusion 11 and the second elastic protrusion 21 are symmetrically arranged. Figure 4 As shown, at this time, the parts of the seal 3 where the first elastic convex groove 11 and the second elastic convex groove 21 contact are completely overlapped, and the width of the overlap area 34 is the width of the groove top surface of the first elastic convex groove 11 or the second elastic convex groove 21. The larger the width of the overlap area 34, the larger the corresponding sealing contact surface, and the better the sealing effect. However, in actual situations, there will be assembly tolerances, and the first metal plate 1 and the second metal plate 2 of adjacent single cells will be offset. Figure 5 As shown, the first elastic protrusion 11 and the second elastic protrusion 21 are not completely aligned. The sealing structure provided by each embodiment of the present invention can absorb a large assembly tolerance, and an ideal sealing effect can be obtained by ensuring that the width D of the overlap area 34 is greater than or equal to 0.5 mm.

[0043] In an ideal situation, the first elastic convex groove 11 and the second elastic convex groove 21 are symmetrically arranged, and the deformation of the two after being subjected to force is also symmetrical. However, due to the existence of assembly tolerance, in actual situations, the deformation of the first elastic convex groove 11 and the second elastic convex groove 21 is generally different, and the first elastic convex groove 11 in some adjacent single cells has a larger deformation, while the second elastic convex groove 21 in other adjacent single cells has a larger deformation, so that the consistency of the sealing structure between the single cells cannot be guaranteed. To solve this problem, in some preferred embodiments, the first elastic convex groove 11 and the second elastic convex groove 21 are designed to have different sizes, such as Figure 5 As shown, the width of the top surface of the first elastic groove 11 is greater than the width of the top surface of the second elastic groove 21, and the wall thickness of the first elastic groove 11 is greater than the wall thickness of the second elastic groove 21. In this way, when the first elastic groove 11 and the second elastic groove 21 are subjected to the same force, the deformation of the second elastic groove 21 of each single cell will always be greater than the first elastic groove 11, so that the sealing structure between the single cells after assembly is consistent, the metal plate is subjected to uniform force, and the performance of each single cell is uniform.

[0044] The pressure required for assembling the battery stack sealing structure provided by the above embodiment is greatly reduced compared with the existing pressure-type sealing structure, the cost of assembly equipment and sealing materials is reduced, and it is easy to disassemble and assemble. After assembly, the seal 3 has a small deformation, and the single cells in the battery stack can be disassembled and reassembled while still ensuring the sealing performance. It has a good prospect for industrial application and promotion.

[0045] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents. However, these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A stack sealing structure, characterized in that: The invention comprises a first metal plate (1), a second metal plate (2) and a sealing member (3); the first metal plate (1) is a cathode / anode plate of a single cell; the second metal plate (2) is an anode / anode plate of another adjacent single cell; the sealing member (3) is arranged between the first metal plate (1) and the second metal plate (2); the sealing member (3) comprises a first adhesive layer (31), an elastic layer (32) and a second adhesive layer (33) which are stacked; the first metal plate (1) has a first elastic convex groove (11) protruding toward the sealing member (3); the second metal plate (2) has a second elastic convex groove (21) protruding toward the sealing member (3); the first adhesive layer (31) is bonded to the groove top surface of the first elastic convex groove (11); and the second adhesive layer (33) is bonded to the groove top surface of the second elastic convex groove (21).

2. The stack sealing structure according to claim 1, characterized in that: The material of the first adhesive layer (31) and the second adhesive layer (33) is pressure-sensitive adhesive, and the material of the elastic layer (32) is rubber.

3. The stack sealing structure according to claim 2, characterized in that: The thickness of the elastic layer (32) ranges from 300 to 600 μm.

4. The stack sealing structure according to claim 1, characterized in that: The projection of the sealing member (3) on the first metal plate (1) covers the first elastic convex groove (11), and the projection of the sealing member (3) on the second metal plate (2) covers the second elastic convex groove (21).

5. The cell stack sealing structure according to any one of claims 1 to 4, characterized in that: The cross-sections of the first elastic convex groove (11) and the second elastic convex groove (21) are isosceles trapezoids with upper base angles ranging from 120° to 160°.

6. The cell stack sealing structure according to claim 5, characterized in that: The width of the groove top surface of the first elastic convex groove (11) ranges from 1 to 2 mm, the width of the inclined surface of the first elastic convex groove (11) ranges from 0.4 to 0.6 mm, the width of the groove top surface of the second elastic convex groove (21) ranges from 1 to 2 mm, and the width of the inclined surface of the second elastic convex groove (21) ranges from 0.4 to 0.6 mm.

7. The stack sealing structure according to claim 6, characterized in that: The sealing member (3) has an overlap area (34) that is in contact with both the groove top surface of the first elastic convex groove (11) and the groove top surface of the second elastic convex groove (21).

8. The stack sealing structure according to claim 7, characterized in that: The width of the overlap area (34) is greater than or equal to 0.5 mm.

9. The cell stack sealing structure according to claim 5, characterized in that: The width of the groove top surface of the first elastic convex groove (11) is greater than the width of the groove top surface of the second elastic convex groove (21), the width of the groove top surface of the first elastic convex groove (11) is greater than the width of the groove top surface of the second elastic convex groove (21), and the wall thickness of the first elastic convex groove (11) is greater than the wall thickness of the second elastic convex groove (21).

10. A battery stack, characterized in that: It comprises a battery stack sealing structure as described in any one of claims 1-9.

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